This invention relates to an integrated circuit construction for mounting high density integrated circuit elements.
As information processing apparatus are recently requiring better and better performance, the packing density of memory, logic and other devices constituting the apparatus is drastically increased. As the packing density increases, the amount of heat per unit volume increases. The effective removal of this heat becomes a problem. Most of the information processing apparatus used at present, however, have forced-air cooling systems using a fan with about 0.03 W/cm.sup.3 of cooling capacity and have an upper limit on density since a passage for the flow of air must be provided for each substrate.
To overcome this defect, a ceramic wiring substrate of heat pipe structure (Laid open Japanese Pat. publication No. 78670/79) has been proposed. This heat pipe structure substrate has a cavity on the inner surface of which is disposed a capillary structure called a wick. The interior of this cavity contains an appropriate amount of working fluid such as pure water, alcohol, etc., decompressed to a predetermined vapor pressure and sealed. The ceramic substrate has radiating fins at the end and supports integrated circuit elements mounted on it.
The integrated circuit device thus constituted does not need a circulation of cool air through the element mounting zone, but can separate the element mounting zone from the heat radiating zone so that the element mounting zone can be densely packed. However, since the integrated circuit elements are mounted on the ceramic substrate through adhesives such as alloy solder, resin, etc., heat which is produced by the integrated circuit elements and which reached the wick within the cavity encounters a large thermal resistance. Thus, to reduce the thermal resistance encountered in mounting these high density integrated circuit elements on the ceramic substrate, a higher air velocity and therefore a large-scale cooling device such as a fan or the like are disadvantageously needed.